SIAMP - toilet filling very slowly

[DanielJMorse]

Hi everyone.

Im not particularly great at DIY, so please accept my apologies in advance.

I have a toilet with a siamp filling contraption. Recently, the toilet has been flushing fine, but then filling really slowly, and now when I flush it it doesnt fill using the normal method - but the only water coming into the tank is from a tiny jet.

I have found a previous post, but my problem is different to this which is the reason for the new post.
//www.diynot.com/forums/viewtopic.php?t=187346&start=0

My filling contraption is identical to this:
here and here
I have unscrewed the ridged nut as in the picture, and the diaphragm washer/valve is absolutely fine - no breakages or cuts, completely sealed.
I have also removed the cap with the off-white coloured washer as also seen in the picture to the right of the ridged nut, and there are no breakages to this either.

I'll talk through what I do to try and give a better idea as I can make it intermittently work.
OK, so assume I have played with the input pipe and it is working. So, I flush the toilet, the water drains and then fills normally, I get the large volume of water coming from the bottom of the siamp fill contraption, and also a small jet of water from the input with the diaphragm valve. When the water reaches the required level, the arm closes the diaphragm valve, stopping the input of water.
However, if I flush the toilet again now, the water drains but it does not re-fill. The only water coming back in to the tank now is from the tiny high pressure diaphragm valve bit..

Now, I can make it work again. I have to turn off the water from the main pipe going into the toilet, remove the cap/washer (right of the ridged nut on the pictures), and take off the cap underneath this, put it back on and put the cap/washer back on, then turn the main pipe water back on, it will fill normally.. I get both the main water input from the bottom of the contraption, and the tiny jet of water until it reaches required fill level where the arm then makes the diaphragm valve stop the input. Now, if I flush the toilet again, it is not likely to re-fill..

I spoke to B&Q who were absolutely useless and tried to give me a washer that didnt even fit.. and they recommended a diaphragm valve - but there are no breakages or cuts etc - that looks absolutely fine. I then went to another plumbing company (PTS) and the guys recommended changing the whole thing, or applying some grease to the up/down bit of the main pipe (which I did not understand at all..)

Can you please give me any advice, I can take more pictures or try to describe more clearly if it doesn't make sense.
Thanks in advance
Daniel

 

[DanielJMorse]

PS, this is what the PTS recommended as a replacement
http://www.screwfix.com/p/fluidmast...m_mmc=AffiliateWindow-_-DeepLink-_-Na-_-58258

 

[Charnwood]

PS, this is what the PTS recommended as a replacement
http://www.screwfix.com/p/fluidmast...m_mmc=AffiliateWindow-_-DeepLink-_-Na-_-58258

So would I.

 

[DanielJMorse]

PS, this is what the PTS recommended as a replacement
http://www.screwfix.com/p/fluidmast...m_mmc=AffiliateWindow-_-DeepLink-_-Na-_-58258

So would I.

Thanks, but is there a fix as opposed to having to replace the whole thing?

 

[spareshunter]

Most probably filter blocked at inlet end. Take advice and replace with fluidmaster easy to repair, unblock or replace in the future.